Evidence suggests that the incidence of renal failure due to hypertension is 6-7 times higher in black than in white patients. It has been proposed that the renal hemodynamic and histologic changes occurring as a consequence of hypertension may differ in black from white patients with essential hypertension. The hypothesis to be tested in these studies is that substantial renal hemodynamic, and anatomic differences exist between black and white patients with essential hypertension. Moreover, we will test the hypothesis that some antihypertensive agents, may have a different impact on the progression of renal disease in black patients. To test this hypothesis we propose to examine in a population of predominantly black patients with hypertension and mild to moderate renal insufficiency (serum creatinine between 1.5 and 5 mg/dl for males, and 1.2 to 4.5 mg/dl for females: 1. The clinical, biochemical, renal hemodynamic, and renal pathologic parameters in blacks with essential hypertension. 2. The predictive value of microalbuminuria and proteinuria for progression of renal disease in these patients. 3. The effect of stepped-care treatment with various antihypertensive agent's (a diuretic, a calcium channel blocker, or an ACE-inhibitor) on blood pressure, and various clinical, biochemical, and renal hemodynamic parameters. 4. The effect of currently acceptable good and effective blood pressure control [ Mean arterial pressure (MAP) of 107 mmHg] as compared with a lower level of blood pressure control (MAP of 93 mmHg) on the progression of renal disease in this patient population. 5. The issue of compliance and retention in a prolonged clinical trial.